1. Field of the Invention
The present invention relates to a process for preparing 4-tert.-butylcyclohexanol containing the larger amount of the cis-isomer by hydrogenating 4-tert.-butylphenol under specific conditions. The present invention also relates to a process for preparing 4-tert.-butylcyclohexyl acetate by acetylating 4-tert.-butylcyclohexanol which is obtained by the process described above.
2. Description of the Prior Art
4-tert.-Butylcyclohexyl acetate is widely used as a perfume for cosmetics including soaps, and fragrance of its cis-isomer is more favorable than that of its trans-isomer. To prepare 4-tert.-butylcyclohexyl acetate having a high cis-isomer content, it is desired to provide a process for preparing 4-tert.-butylcyclohexyl containing the larger amount of the cis-isomer because 4-tert.-butylcyclohexanol is used as a raw material of 4-tert.-butylcyclohexyl acetate.
In general, 4-tert.-butylcyclohexanol is prepared by hydrogenating 4-tert.-butylphenol.
JP-B-42-13938 discloses a process for preparing 4-tert.-butylcyclohexanol comprising catalytically reducing 4-tert.-butylphenol in the presence of a rhodium base catalyst.
MARUZEN OIL TECHNICAL REVIEW (MARUZEN SEKIYU GIHO) (1971) page 77 discloses a process for preparing 4-tert.-butylcyclohexanol comprising hydrogenating 4-tert.-butylphenol in the presence of various transition metals of the 8 to 10 Groups of the Periodic Table.
JP-A-54-122253 discloses a process for preparing a cis alkylcyclohexanol comprising hydrogenating an alkylphenol in the presence of a ruthenium-alumina catalyst.
U.S. Pat. No. 2,927,127 discloses a process for preparing 4-tert.-butylcyclohexanol comprising hydrogenating 4-tert.-butylphenol in ethanol in the presence of the rhodium catalyst.
JP-A-3-173842 discloses a process for preparing 4-tert.-butylcyclohexanol comprising hydrogenating 4-tert.-butylphenol in the presence of a combined catalyst of Rh supported on a carrier and a boron fluoride type acid such as HBF.sub.4.
However, the cis-isomer content in 4-tert.-butylcyclohexanol which is prepared by the processes disclosed in JP-B-4213938, MARUZEN OIL TECHNICAL REVIEW and JP-A-54-122253, is still insufficient. The process of U.S. Pat. No. 2,927,127 achieves a high cis-isomer content, but the reaction must be performed under a high hydrogen pressure. Further, in the process of JP-A-3-173842, since the process uses the boron fluoride type acid, a workload is required to recover fluorine and boron, and generated acids such as HF corrode a production equipment.